- EBV viral load greater than or = to 10,000 copies per 10xe6 peripheral blood mononuclear cells (PBMCs) as determined by quantitative polymerase chain reaction (qPCR). If there is any clinical suspicion that a subject who is EBV seronegative and with EBV PCR <10,000 copies per 10xe6 PBMCs has symptoms consistent with infectious mononucleosis prior to administration of study drug, then a monospot test result must be negative before the subject can be dosed.